Trocar system

ABSTRACT

A trocar system (10) comprises a trocar tube (11), a trocar plunger (12) and a valve housing (13) formed on the end of the trocar tube (11) facing away from the patient. The trocar tube (11) is produced from a flexible material which is stabilized by a spiral (22). The trocar tube (11) has a taper at the end (21) next to the patient which can be supported at a circular shoulder (15) with the trocar plunger (12) inserted into the trocar tube (11). The trocar tube (11) can be bent in the direction of arrow (23) and stretched in the direction of arrow (24).

BACKGROUND OF THE INVENTION

The invention concerns a trocar system having a flexible trocar tubedefining a lumen, a trocar plunger and a valve mechanism formed at theend of the trocar tube facing away from the patient through the valvehousing of which the trocar plunger can be inserted into the trocartube.

These types of trocar systems are known in the art from DE-OS 43 12 147.These trocar systems comprise an obturator made from rust-free steel orfrom another rigid material and a cannula made from plastic, such asPTFG, polyurethane or PVC. The cannula made from this type of plastichas an open proximal and open distal end and is flexible to facilitatethe introduction of a curved surgical instrument through the cannulainto the body cavity without having to increase its inner diameter.

Known in the art from DE-OS 41 34 655 is an atraumatic cannula having amandrin with an outer cross section and a shaft with an inner crosssection which are tapered in the vicinity of the shaft tip such that,when introducing the cannula into the tissue, the pressure on themandrin facilitates contact between its tapering and the tapering of theshaft to "carry" same and cause stretching thereof while avoidingdisplacement of its material.

The trocar system in accordance with DE-OS 43 12 147 is fundamentallysuitable for the introduction of a curved operation instrument into ahollow body region. However, the operation instrument can cause back andforth motion or displacement of the trocar tube within the tissue. Forthis reason it is necessary for the trocar tube to be securely anchoredin the tissue, in particular, when very strongly curved instruments areintroduced.

It is therefore the underlying purpose of the invention to furtherimprove conventional flexible trocar systems in such a fashion that theanchoring of the trocar tube within the tissue is improved and to alsoguarantee the possible introduction of strongly curved instruments intothe trocar tube.

SUMMARY OF THE INVENTION

This purpose is achieved in accordance with the invention in that thetrocar tube is stretchable with respect to the axial length and thetrocar tube is tapered at the end next to the patient, the taperinterlockingly engaging a circular step or a conical section at the tipof the trocar plunger.

The taper is formed in such a fashion that it is capable of closeinterlocked seating in the tip region of the trocar plunger. In thisfashion the tapering engages a circular step or a conical section at thetip of the trocar plunger. The interlocking connection can accept axialforces acting in opposition to the pushing and positioning direction ofthe trocar tube. A flange is formed at the end of the trocar tube facingaway from the patient which can seat in the valve housing. The flangecan be strengthened by inlays in the flange material or by support ringsand is held within the valve housing in an axially non-displaceablefashion. In further embodiments of the invention, it would also bepossible for the trocar tube to be held within the valve housing in arotatable manner.

A trocar configured in accordance with this technical teaching has theadvantage that the trocar tube can be pretensioned at the trocar plungerin a defined fashion. It is therefore possible to prevent anunacceptable excessive stretching of the trocar tube. In the event thatthe trocar tube is pretensioned it can, for example, be connected in adetachable fashion to the trocar plunger via the valve housing. Towardsthis end, the trocar tube is supported on the circular step of thetrocar plunger and is preferentially attached at the other side to thetrocar plunger via the end in proximity to the machine. In the eventthat the trocar plunger shaft is thinner than its tip, it is possiblefor the trocar plunger to easily slide within the trocar tube until thetip of the trocar plunger interlocks with the trocar tube taper.

An additional advantage of a trocar configured in accordance with theinvention is that the cross section of the trocar tube is reduced whenthe trocar tube is lengthened. After removal of the trocar plunger fromthe trocar tube same contracts again and is thereby shortened. In thisfashion the cross section of the trocar tube is increased. This increasein cross section increases the strength with which the trocar tube isanchored in the tissue. In this fashion the traumatic effect of the tubewithin the tissue is reduced and the attachment or anchoring of thetrocar tube within the tissue is significantly increased to preventslipping of the trocar tube during the operation.

The improved anchoring of the trocar tube within the tissue alsoadvantageously prevents gas from unintentionally escaping out of thehollow body region.

The trocar system in accordance with the invention also has thesubstantial advantage that the trocar tube is guided without compressioneven in the event that large axially directed forces act on the tip ofthe trocar tube bushing. During insertion into a tissue layer, thetrocar plunger carries the trocar tube along with it without having thetrocar tube be displaced in a direction opposite to that of theplacement and pushing direction. In the event that the trocar tube andthe trocar plunger are adapted to each other in accordance with theinvention, it is also possible to position tube shafts having astiffness of insufficient strength with respect to an axially directedforce.

In the event that the trocar tube is manufactured from an elasticpipe-shaped material which is adapted for suitable acceptance of radialforces, it is possible to guarantee the gas-tightness both in the shaftregion as well as in the valve region via the rubber elastic sealingring or rings to successfully prevent the danger of an undesirednarrowing of the lumen along the trocar tube. When selecting the shaftmaterial, it is possible to provide for a trocar tube which bends whenthe trocar plunger is removed to accept even strongly curved instrumentswhile preventing, with unchanged lumen, an unacceptable buckling duringintroduction of curved instruments.

In a preferred embodiment of the invention, the trocar tube isconfigured as a spiral jacketed with elastic material whose individualspiral windings are separated from each other, with the elastic materialclosing the intermediate space between the individual spiral windingsalong the axial length of the trocar tube.

The spiral can be configured as a spiral wire spring jacketed with anelastic material having good low friction characteristics. The spiralwire reliably prevents the lumen of the trocar tube from unacceptablychanging when bent to avoid difficulties when inserting an instrument.The spiral can be configured as a ring at the free end next to thepatient which is jacketed, as is the remaining wire insert along theentire length of the trocar tube, with a plastic material to whichtissue is insensitive. The wire insert can be of arbitrary constructionand must not necessarily be configured as a spiral spring.

In a further configuration of the invention the trocar plunger has agreater axial length than the trocar tube in its non-operative state.

This has the advantage that the trocar tube can be lengthened prior toinsertion. If the cross section of the trocar plunger is smaller, withregard to its diameter, than the trocar tube, same can taper in diameterwhen axially stretched. This facilitates insertion of the trocar plungerinto a tissue layer, since the reduced overall cross section likewiseresults in a reduction in the insertion resistance.

In another preferred embodiment of the invention the valve mechanism isheld within the valve housing, same having at least one elastic sealwhich surrounds the trocar plunger within the trocar tube in a gas-tightfashion to cause a gas-tight sealing of the lumen when the trocarplunger is removed.

In the event that one or a plurality of sealing discs are utilized as avalve mechanism, a reduced axial construction height is possible in thevalve region and the sealing region has additional flexibility. Curvedor highly curved surgical instruments of an arbitrary kind can be easilypassed through the trocar tube with a defined lumen, since the sealingdisc or discs do not reduce or block the lumen in the vicinity of thevalve mechanism. It is possible for the sealing rings to give-way underpressure and they can be quickly replaced when needed without additionalexpense.

A further embodiment of the invention comprises a valve housing whichcan be disassembled.

The trocar tube is held and guided within the valve housing. The flangeseats on the housing floor at the inner side of the valve housing.Support rings or sealing discs can be adjacent to the flange. The valvehousing is closed via a housing lid which presses the sealing disc ordiscs against the flange of the tubular shaft. The housing lid can beheld to the valve housing using clamps. The valve housing can be easilydisassembled and cleaned when the clamps are released. Defectiveindividual components can be quickly replaced. Suitable sealing discs orsealing rings can be utilized as sealing means in the valve housing.

In a further advantageous embodiment of the invention all individualcomponents of the trocar system are made from material which can becleaned and sterilized.

This has the advantage that the trocar system in accordance with theinvention can be utilized a plurality of times. If necessary, thesealing means can be replaced to always guarantee the gas-tightbehaviour of the system.

In a further embodiment of the invention, the trocar tube comprisesretention means on the outer peripheral surface, preferentially in thevicinity of the end facing away from the patient, such as, for example,tabs, wings, ring-shaped elements, or an inflatable cuff. This has theadvantage that the trocar tube in accordance with the invention can, forexample, also be secured in the stomach wall of a patient. In the eventthat the seated trocar tube is displaced in an inappropriate fashion,the retention means oppose this motion. A significant self-fixing of thetrocar tube in accordance with the invention is also already achieved bythe fact that the extended positioned trocar tube strives to return toits original length when the trocar plunger is removed. In this fashion,the outer diameter of the trocar tube increases and the outer contoursof the trocar tube penetrate into the immediately adjacent tissue. Inthis fashion, the trocar tube is securely held in position.

With the trocar system in accordance with the invention, flexible trocartubes can be securely supported at the trocar plunger end region frominsertion up to final positioning to avoid an unallowed compression ofthe trocar tube material. A reduced constructional height in thevicinity of the valve mechanism (discs and/or rings) is achieved via thesealing means. This allows for the additional introduction ofinstruments with large radii of curvature. The trocar tube in accordancewith the invention is centered during placement and automatically seatsafter removal of the trocar plunger. A defined pretensioning of thetrocar tube and the attachment at the trocar plunger can be preparedprior to use. An impermissible excessive stretching of the trocar tubein the axial direction does not occur. In addition to the requiredflexibility, the system is gas-tight along the entire length of thetrocar tube as well as in the vicinity of the valve mechanism and easycleaning and disassembly of the entire system is likewise guaranteed.Individual components, such as the sealing discs, are easily accessibleand can be easily replaced.

In accordance with the invention not only sealing rings but also sealingdiscs can surround the trocar plunger in a gas-sealing-fashion withinthe valve housing. Sealing discs have the advantage of being able toautomatically close the lumen in a sufficiently gas-tight manner whenthe trocar plunger is retracted.

Further advantages can be derived from the description and theaccompanying drawing. The above mentioned features as well as those tobe described below can be used in accordance with the inventionindividually or collectively in arbitrary combination. The embodimentsmentioned are not to be considered as exhaustive enumeration, ratherhave exemplary character only.

The invention is represented in the drawing and explained in connectionwith embodiments.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 shows a trocar system in accordance with the invention comprisinga trocar tube having a valve housing and a trocar plunger;

FIG. 2 shows a trocar tube with opened valve housing which accepts theindividual components shown in the figure.

DESCRIPTION OF THE PERFERRED EMBODIMENT

The figures of the drawing show the object in accordance with theinvention in a partially schematic fashion and the dimensionsillustrated are not to be strictly taken to scale.

FIG. 1 shows a trocar system 10 comprising a trocar tube 11, a trocarplunger 12 and a valve housing 13 connected to the trocar tube 11. Acircular shoulder 15 is formed in the tip region 14 of the trocarplunger 12 to which a conical mandril 16 is adjacent. A shaft section 17of the trocar plunger 12, which extends from the tip region 14 up to ahandle 18, has a reduced diameter compared to tip region 14. The handle18 is formed on the trocar plunger 12 opposite to the tip region 14 atwhich the trocar plunger 12 can be grasped and pushed through the valvehousing 13 into the trocar tube 11.

A sealing cap 20, formed on the valve housing 13, is made from a rubberelastic material and can sealingly surround the trocar plunger 12 whensame has been introduced into the valve housing 13 and the trocar tubeshaft. The trocar tube 11 is tapered at the end 21 next to the patient.

The trocar tube 11 is manufactured from a spiral 22 surrounded by arubber elastic plastic material. The individual spiral windings areseparated from each other and the gaps between the spiral windings arelikewise filled by the plastic material. The trocar tube 11 is flexiblein the direction of arrow 23 and can also be stretched in the directionof arrow 24. The spiral 22 is preferentially made from a metal spiral.

In the event that a trocar plunger 12, having a length which is greaterthan that of the trocar tube 11 including the valve housing 13, isinserted into the trocar tube 11, it is possible to insert the trocarplunger 12 into the trocar tube 11 only up to the point where thecircular step or shoulder 15 of the trocar plunger 12 lockingly engagesthe taper at the end 21 of the trocar tube 11 next to the patient. Inthe event that the trocar plunger 12 is further inserted in thedirection of arrow 24 with the valve housing 13 being stationary, thetrocar tube 11 stretches in the direction of arrow 24.

The valve housing 13 is constructed in a manner allowing disassemblingof same and is held together by means of clamps 25. Two clamps 25 areshown in FIG. 1.

FIG. 2 shows a trocar tube 11 and a valve housing 13 opened and withdisassociated individual components arranged within the valve housing13. The trocar tube 11 can be inserted into the valve housing 13 via thetaper at the end 21 next to the patient. A flange 26 is formed on thetrocar tube 11 and seats on a housing floor 27 of the valve housing 13when the trocar tube 11 is inserted. With the trocar tube 11 beinginserted into the valve housing 13, a support ring 28 made from a toughelastic material or from a material having a stable shape is placed ontothe flange 26 for stabilizing purposes. A sealing ring 29, at which thefirst sealing disc 30 and the second sealing disc 32 are supported, isplaced onto the support ring 28. The sealing discs 30, 31 have slits30', 31' to allow the trocar plunger 12 to penetrate through the valvehousing 13 when the valve housing 13 is closed. The slits 30', 31' canbe positioned on top of each other rotated with respect to each other by90°. The valve housing 13 can be closed by means of a housing lid 32which is pressed onto the inserted components within the valve housing13 by means of clamps 25. A tubular shoulder 33 is formed on the housinglid 32 onto which the rubber elastic sealing cap 20 can be placed.

Retention means can be provided for on the outer surface of the trocartube 11 to securely fix the position of the trocar tube 11 within thetissue. Tabs or ring-shaped flanges are suitable as retention meanswhich open when the trocar tube 11 is retracted out of the tissue togenerate an opposing force. In the event that the force exercised duringretraction of the trocar tube 11 exceeds the maximum opposing force,these retention means can flip-over in the retraction direction of thetrocar tube 11 to seat against the outer surface. In the event that themaximum retaining force of the retention means is exceeded, it ispossible for the trocar tube 11 to be removed from the tissue withoutexercising additional increased force. Spirals introduced onto the outersurface of the trocar tube or an inflatable cuff are suitable asretention means. The retention means are preferentially formed below thevalve housing 13 at a certain separation therefrom and along a certainaxial length on the trocar tube shaft.

A trocar system 10 comprises a trocar tube 11, a trocar plunger 12 and avalve housing 13 formed at the end of the trocar tube 11 facing awayfrom the patient. The trocar tube 11 is produced from a flexiblematerial which is stabilized by a spiral 22. The trocar tube 11 has ataper at the end 21 next to the patient which can be supported at acircular shoulder 15 with the trocar plunger 12 inserted into the trocartube 11. The trocar tube 11 can be bent in the direction of arrow 23 andstretched in the direction of arrow 24.

We claim:
 1. A trocar system comprising:a trocar plunger having one of acircular step and a conical section at a tip thereof; a flexible trocartube defining a lumen, said tube being stretchable along an axial lengththereof, said tube having a taper at an end proximate to a patient, saidtaper interlocking with at least one of said circular step or conicalsection; and a valve mechanism formed at an end of said trocar tubefacing away from a patient, said valve mechanism having a valve housingadapted for passage of said trocar plunger for insertion of said trocarplunger into said trocar tube.
 2. The trocar system of claim 1, whereinsaid trocar tube comprises a spiral jacketed in elastic material.
 3. Thetrocar system of claim 2, wherein said spiral comprises individualspiral windings and said elastic material closes intermediate spacesbetween said spiral windings along an axial length of said trocar tube.4. The trocar system of claim 1, wherein said trocar plunger has anaxial length greater than an axial length of said trocar tube in anon-operative state.
 5. The trocar system of claim 1, wherein said valvemechanism is held within said valve housing, said valve housingcomprising an elastic seal surrounding said trocar plunger within saidtrocar tube in a gas-tight fashion, said elastic seal closing said lumenin a gas-tight fashion when said trocar plunger is removed.
 6. Thetrocar system of claim 1, wherein said valve housing is adapted fordisassembly thereof.
 7. The trocar system of claim 1, wherein saidtrocar plunger, said trocar tube, and said value mechanism aremanufactured from material which can be cleaned and sterilized.
 8. Thetrocar system of claim 1, wherein said trocar tube comprises retentionmeans on an outer peripheral surface.
 9. The trocar system of claim 8,wherein said retention means are located at an end facing away from apatient.
 10. The trocar system of claim 8, wherein said retention meanscomprise at least one of tabs, wings, wing-shaped elements and aninflatable cuff.